The health status of obese individuals in Canada

OBJECTIVE: To determine whether there is a clinically relevant difference i n the health state utilities of obese and non-obese individuals as measured by the Health Utility Index Mark ill. METHODS: Secondary analysis of the population-based, cross-sectional, inter viewer-administered National Population Health Survey (NPHS), 1996-1997. A probability sample of house-dwelling Canadians, excluding populations on Fi rst Nations Reserves, Canadian Armed Forces Bases, the Yukon and Northwest Territories, and long-term residents of hospitals or residential care facil ities. The sub-sample used in this analysis consisted of 38151 respondents( 52.4% male) between the ages of 20 and 64 y, excluding pregnant women. Heal th Utilities Index-Mark III (HUI3) scores were used to define normal weight (body mass index (BMI) 19-24.9 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)), obese (BMI 30-34.9 kg/m(2)), and morbidly obese (BMI greater than or equal to 35 kg/m(2)) individuals. HUI3 scores were age- and gender-standardized. RESULTS: The overall prevalence of obesity (BMI greater than or equal to 30 kg/m(2)) in this Canadian population was 13.3%. The average difference in HUI3 scores between normal weight and morbidly obese respondents was 0.04 ( P < 0.001). Statistically significant (P < 0.05) differences across BMI cat egories were found in each of the eight component attributes of the HUI3. T he attributes with the most substantial difference between normal and obese patients were cognition, mobility and pain. All demonstrated a greater tha n or equal to 2-fold increase in the proportion of individuals in poorer cl assifications of health when normal weight respondents were compared with t he morbidly obese. The magnitude of the decrement in utility ratings associ ated with obesity was comparable with other chronic non-cardiovascular cond itions such as migraine or colitis. CONCLUSION: The results indicate that changes in self-rated health status a ppear to be due to significant changes across several relevant domain attri butes. Obesity has a significant impact on both quality of life and health.